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DIY: Do It Yourself Post here to share or improve your wrench turning skills! All BMW E46 DIY tips, tales, and projects discussed inside. Learn to work on your car and know the right BMW parts you will need!

After seeing all of these threads on people asking why their cars are making a whistling sound at high rpm or while driving, it got me wondering what has caused this and I did some research and found that it was the lower intake boot that gets old and starts to crack, letting in unfiltered air under hard or moderate acceleration, which in turn leads to that loud whistle you may be experiencing. My car does this too so therefore I decided to fix the problem. I have made a DIY on how to do this to help fellow e46Fanatics who are experiencing this problem to fix it. Here is my DIY. Enjoy.

Difficulty: It is simple if you know your way around the engine and if you have disassembled the intake of your car before, I'd say this repair will take the average person anywhere from 45 minutes to 1 hour 30 minutes.

Step 1: Remove the little clamps holding together the front part of your intake. Use the needle nosed pliers to help get the clamps out.

Step 2: Remove the first part of your intake. It should look something like this when you are done.

Step 3: Remove the two bolts holding your air box in by using the 10mm socket and wrench with an extension to make it easier.

Step 4: Loosen the metal band that is around the upper intake hose with the flathead screwdriver.

Step 5: Disconnect the MAF (mass airflow sensor) by pressing down on the small metal bar on top of the connector and pulling the connector away.

Step 6: Pull apart the uppper intake hose from the back of the MAF and once disconnected remove your entire airbox.

Your engine should look like this by now.

step 7: Now its time to remove the cabin filter, you need to loosen these three clamps by pushing down and turning counter-clockwise.

The clamps should pop up if you loosened them the right way.

Step 8: Remove the lid of the cabin filter by lifting up and pulling it out.

remove the filter also.

Step 9: Now you will see 4 TORX bolts.

Remove them with a T30 TORX bit.

before removing the cabin filter, remove a black clip that is on the bottom of it holding some wires, just unclip it and pull the wires out.

Step 10: After removing all 4 TORX bolts, remove the entire cabin filter assembly by lifting up and pulling it out.

By now your engine bay should be looking something like this.

Step 11: Loosen the metal bands around the bottom and top of the upper intake hose and the intake boot, also pull out the hose leading into the upper intake hose.

Step 12: Remove the upper intake hose by pulling it off, you might need to pull hard to get it off, but once its off you will see the intake boot that you will be replacing. I circled one of the metal bands on the back of the small hose on the intake boot, try and loosen this the best you can and pull that hose off.

You may want to remove this black wall that is near the brake booster, it gets in the way and when removed will allow you better access to the screws to loosen the metal bands around the back of the intake boot. Just remove this piece by turning both screws that I've circled and pull them out, then just lift this piece out of the way.

Step 13: Feel around the back of the intake boot for the bolt on the metal band and try and see if you can see it, then loosen that and pull the intake boot off as hard as you can, its not easy to get off but eventually it will come off.

Finally got the SOB off.

This is what it will look like with the intake boot removed. To install the new one just put the metal bands from the old one on the new one and push the new one on over the big hole first then push the small tube on next, make sure you put it on really secure as you don't want any air leaks which would defeat the purpose of this repair.

New intake boot on!

Now to put everything back together, just follow the steps backwards and if you did it right it should be looking like this.

Finally, check over everything and make sure nothing is loose and then close your hood and start the car, let it warm up, the idle should be a lot smoother now, go for a drive and enjoy the quiet sound of your engine minus the annoying whistle.

I hope this DIY has helped you a lot. If you have any questions feel free to PM me and ill be glad to answer them for you.

This is the type of write ups that really helped me in the beginning working on my own car.

I saw you could save a minute of time in step#9 where you were removing the wires off of the cabin filter. Instead of popping the clips to remove the wires, you can insert flat head screwdriver up and under the backside of each end and pop off the entire wire holding assembly. This will keep the casing intact with the wires. To reinstall just 2 clicks it pops back in.

Step#11, like URBANKYLEBOY said that could be a PITA. It appeared that both of your screw heads of the metal bands going onto the Tube Elbow were faced up!!! Either you or whoever replaced the Tube Elbow in the past left them facing up for future ease!!!!

Like FRANZ stated if you have to replace again, good idea to do the CCV cleaning and the DISA reseal since you are perfectly down in there with all the parts easily exposed with the Tube Elbow out.

Excellent tutorial, we cant have to many of these. Consider placing this in the DIY section.

However, you do not need to remove cabin filter its not even a little in the way, no idea why you did this. Also, you dont need to remove the air filter box. Once the MAF is out, there is plenty of room.

So just do step 4-6, and thats it.

I must say though, I cleaned my throttle body right when i first bought this car with 0 input. Taking off the intake boot could not be more straight forward. If you need a tutorial for this, maybe you shouldn't be working on your car.

Thx for the DIY! Did mine yesterday, definitely need a 6mm wrench to loosen those bands near the throttle body, but finally got it out. No more whistling and no more shaky RPMs on startup. Cleared SES and hopefully the light won't come back!